Method of making reinforced flexible hose with leakage indicator

ABSTRACT

A reinforced flexible hose that has at least one layer of stainless steel threads braided about the outer surface of the inner core and a transparent flexible polymeric covering located over the braided stainless steel threads, thereby protecting them from abrasion and corrosion. The covering is not in intimate contact with the circumference of each thread thereby trapping pockets of air between the covering and the threads. A moisture sensitive compound is dispersed through the stainless steel threads under the transparent covering. When the compound becomes wet, it changes from a first color to a second color indicating that the hose has failed.

RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.12/185,608, filed Aug. 4, 2008.

FIELD OF INVENTION

The invention pertains to reinforced hoses. More particularly, theinvention relates to plastic core hoses with braided reinforcing,protective outer coverings and an integral leakage indicator for use inplumbing applications and related uses.

BACKGROUND OF THE INVENTION

A number of applications are best served by flexible hoses. Mostnotably, hoses connecting fixed plumbing outlets to vibrating machineryor appliances require the use of flexible hoses to prevent cracking andresultant leaks. Resilient materials, including various types of rubberand plastic, have been employed in situations requiring flexible hoses,however, a number of problems are typically encountered. The flexiblematerials employed in such hoses tend not to be as strong and resistantto higher pressures as solid, non-flexible materials. Further, suchmaterials tend to stretch and further weaken under pressure, puttingstrain upon the points of attachment of these hoses to fittings andcouplings. A number of methods have been developed to give flexiblehoses the strength and durability needed while maintaining the requiredflexibility.

A further problem associated with hoses connecting vibrating or movingequipment, such as washing machines and dishwashers is that the hosesmay develop cracks, defects and other problems that result inpotentially damaging leakage. Often these leaks are small at first andare difficult to detect. If such leaks go undetected, they may becomecatastrophic, causing major damage to walls, floors, etc. The presentinvention addresses this problem by providing a visual indicator of anyleak in the hose. A simple inspection of the color of the hose, visiblethrough the transparent covering, will allow a defective hose to betimely replaced.

U.S. Pat. No. 4,699,178 issued to Washkewicz discloses a high burststrength flexible composite hose having low volumetric expansion underpressure which includes a thermoplastic core tube, one or more braidedreinforcing layers of high strength aramid yarn having a tensile modulusof elasticity of about 17,000,000 psi and a tenacity of more than 20grams per denier at room temperature, and an outer cover of elastomericmaterial.

U.S. Pat. No. 4,111,237 issued to Muntzner et al. describes a hydraulicbrake hose comprising a polychloroprene inner tube, a reinforcing braidof twisted glass fiber yarn around the tube, a styrene-butadienecopolymer rubber cushion layer over the glass braid, a secondreinforcing braid of nylon fiber yarn over the cushion layer and a coverlayer of polychloroprene rubber.

U.S. Pat. No. 5,803,129 issued to Coronado et al. discloses an improvedreinforced hose for conducting fluids and gases, and a method ofmanufacturing that hose. The improved reinforced hose includes aninterior tube having an inner bore and an outer surface. The improvedreinforced hose also includes an outer covering disposed directly aboutthe outer surface of the interior tube. Such outer covering includes oneor more layers of plastic threads, which are formed by disposing aplastic substance about core material.

U.S. Pat. No. 5,381,834 issued to King describes a hose assembly of thetype for carrying high-pressure fluids therethrough. The hose assemblyincludes a tubular member and a pair of coupling members. The tubularmember includes an inner liner of a fluorocarbon polymer. Yarnsfabricated from fibers, including glass fibers and Aramid fibers, arebraided together about the exterior of the inner liner to form a braidedlayer. The assembly further includes an outer fluorocarbon coatingdispersed throughout the braided layer to prevent kinking or permanentdeformation in the inner liner, in addition to preventing the crushingof the yarns when the ends are crimped to receive the coupling members.A conductive strip is formed on the inner liner for dissipatingelectrical charges that may accumulate in the inner liner.

U.S. Pat. No. 5,142,782 issued to Martucci describes a method of makinga lightweight hose assembly including a step of extruding the innerliner. A nonmetallic material is then braided about the exterior of theliner. The inner liner and braided layer are then passed through areservoir containing a solution of the fluorocarbon polymer. The solventis then removed, leaving a fluorocarbon polymer coating dispersedthroughout the braided layer.

U.S. Pat. No. 4,915,762 issued to Berlincourt et al. discloses a hosecomprising an inner plastic tube covered by at least one braiding offilaments disposed in helically crossed layers around the inner tube,characterized in that the filaments are made of plastics and are sodeformed in their right cross-section that the gap between any twoadjacent layers which extend in the same direction as one another is atleast 100% filled. The invention also relates to a process for theproduction of the hose.

U.S. Pat. No. 4,952,262 issued to Washkewicz, et al. discloses a methodof hose construction and product formed thereby consisting of anextruded thermoplastic core tube having ferrometallic wire reinforcementwindings thereon which are closely wound and providing minute spacesbetween the wires. The reinforced core tube structure is elevated intemperature by an induction heater which concentrates heating in thewire reinforcement and transfers heat from the wire by conduction to theouter periphery of the core tube. Supplemental conventional heaters maybe used in conjunction therewith to achieve substantial temperatureelevation of the wire reinforcement. Thereafter a thermoplastic cover ispressure extruded over the heated wire reinforcement and forced throughthe minute spaces in the reinforcement into engagement with the coretube periphery. Cool-down establishes a bond between cover, wires andcore tube and a mechanically locked, integral composite hose structure.

U.S. Pat. No. 4,275,768 to Riggs, et al. discloses a longitudinallyextending, circumferentially limited member is disposed upon theexterior surface of a tubular object such as hose, which member has asurface appearance contrasting to that of the exterior surface of thetubular object. Indicia are engraved within the surface of thelongitudinally extending, circumferentially limited member and isrendered prominently visible by the difference in contrast between thetwo surface appearances.

U.S. Pat. No. 4,585,035 to Piccoli discloses a flexible hose having abraided spiral reinforcement layer having one wire braid member whichremains uncrimped during braiding and a second braid member which iscomposed of a relatively flexible, high tenacity material which iscrimped or deformed around the wire braid member at each contact pointin the braided-spiral layer. The hose may be made using a flexiblemandrel technique to produce a light weight hose having improvedflexibility for use in high pressure applications such as in hydraulicsystem components.

The problems with the prior art described above include:

1. It is difficult to obtain good adhesion between the braid and theouter covering because the braid is hard to clean.

2. The outer plastic layer is uneven because it is applied over anuneven braid.

3. The outer plastic layer is typically very thin, of the order of 0.3to 0.5 mm.

4. The outer plastic layer tends to break when the tubes are bent.

5. Stresses on the hose due to vibrating machinery may result in leaksthat, if undetected, may result in major damage to surroundings.

It is an objective of the present invention to provide a flexible hosecapable of withstanding vibration and jarring. It is a further objectiveto provide a hose capable of handling relatively high pressure withoutexpanding in diameter. It is a still further objective of the inventionto provide a hose that will not rust, corrode or oxidize. It is yet afurther objective to provide a hose that will indicate a leakingcondition before such leaks become catastrophic. It is a final objectiveto provide a hose that may be easily and inexpensively manufactured inany desired length.

While some of the objectives of the present invention are disclosed inthe prior art, none of the inventions found include all of theobjectives identified above.

SUMMARY OF THE INVENTION

A reinforced flexible hose is provided. The hose has an interior tubefor conducting a fluid. The tube has an inner bore and an outer surface,at least one layer of stainless steel threads braided about the outersurface and a transparent, flexible polymeric covering. The covering islocated over the stainless steel threads and contacts them tangentially,thereby protecting them from abrasion and corrosion. Pockets of air aretrapped under the transparent polymeric covering and between the strandsof stainless steel. A moisture sensitive compound is provided. Thecompound changes from an initial color to a second color upon contactwith moisture. The compound is dispersed in the pockets of air trappedbetween the threads and the transparent flexible polymeric covering. Theflexible polymeric covering protects the steel braids from corrosion andabrasion. The pockets of air assist in insulating the interior tube andstainless steel braid. Moisture penetrating from the interior tube tothe stainless steel threads, changes the moisture sensitive compound tothe second color, indicating failure of the hose.

In a variant, the interior tube is formed of synthetic polymer material.

In another variant, the interior tube is formed of material selectedfrom the following group: ethylene-propylene-compound diene,acrylonitrile-butadiene, synthetic resinous fluorine, nylon,thermoplastic polyester elastomer, polyurethane, polyvinyl chloride andrubber.

In yet another variant, the stainless steel threads are grouped intodistinct strands that are interwoven to form at least one braided layerof threads.

In a further variant, the strands contain between about two and aboutnine stainless steel threads.

In still a further variant, the gauge of the stainless steel threadsranges from about 0.002 inches to about 0.070 inches.

In another variant, the stainless steel threads are located about theinterior tube under tension and the tension ranges from about 0.5 poundsto about 3 pounds.

In yet another variant, the moisture sensitive compound is selected fromthe group including copper sulfate, cobalt chloride, and cobalt iodide.

In a further variant, the flexible polymeric covering is formed ofmaterial selected from the following group: ethylene-propylene-compounddiene, acrylonitrile-butadiene, synthetic resinous fluorine, nylon,thermoplastic polyester elastomer, polyvinyl chloride, polyurethane andrubber.

In yet another variant, the flexible polymeric covering is about 0.8 to1.0 mm thick. The hose is manufactured as follows.

A. The interior tube is fabricated, preferably by extrusion.

B. At least one layer of stainless steel threads is braided about theouter surface of the interior tube.

C. The flexible polymeric covering is fabricated, preferably byextrusion.

D. The moisture sensitive compound is dispersed between the stainlesssteel threads.

E. The flexible polymeric covering is slipped over the braid. This trapspockets of air between the covering and the braid thereby protecting thebraid from abrasion and corrosion and improving the insulativeproperties of the hose. The moisture sensitive compound alerts the userto any leaks in the hose through a visual inspection.

The hose construction represented in this invention is an improvementover the prior art. Hoses in accordance with this invention have asmooth outer surface which is easier to clean. Since the outer coveringis actually an independent member it is less likely to peel of andsustain damage during bending. Hoses constructed in accordance with thisinvention are thus stronger, more flexible and will inform the user ofany leaks developing in the hose.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the preferred embodiment of theinvention illustrating stainless steel threads braided about an outersurface of a tube and a transparent, plastic polymeric covering;

FIG. 2 is cross-sectional view of the FIG. 1 embodiment illustrating abraided layer of steel threads and the transparent, plastic polymericcovering;

FIG. 3 is a partial, magnified cross-sectional view of the FIG. 1embodiment illustrating the dispersal of the moisture sensitivecompound;

FIG. 3A is a partial, magnified cross-sectional view of the FIG. 3embodiment illustrating the braiding of the steel threads and thedispersal of the moisture sensitive compound;

FIG. 4 is a magnified, cross-sectional view of a strand of stainlesssteel threads; and

FIG. 4A is a perspective view of a magnified, cross-sectional view of astrand of stainless steel threads illustrating the dispersal of themoisture sensitive compound among the threads.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIGS. 1, 2 and 3, 3A, 4 and 4A, a reinforced flexible hose10 is provided. The hose 10 has an interior tube 15 for conducting afluid. The tube 15 has an inner bore 20 and an outer surface 25. Atleast one layer of stainless steel threads 30 are braided about theouter surface 25 and a transparent flexible polymeric covering 35 islocated over the stainless steel threads 30. The flexible polymericcovering 35 is not in intimate contact with the circumference of everythread 30. The flexible polymeric covering 35 only contacts the threads30 tangentially. Thus pockets of air 60 are trapped between the covering35 and the braid 30 thereby protecting the braid 30 from abrasion andcorrosion and improving the insulative properties of the hose 10. Amoisture sensitive compound 32 is provided. The compound 32 changes froman initial color 34 to a second color 36 upon contact with moisture 38.The compound 32 is dispersed in the pockets of air 60 trapped betweenthe threads 30 and the transparent flexible polymeric covering 35. Whenmoisture 38 penetrates from the interior tube 15 to the stainless steelthreads 30, the moisture sensitive compound 32 will changes to thesecond color 36, indicating failure of the hose 10.

In a variant, the interior tube 15 is formed of synthetic polymermaterial.

In another variant, the interior tube 15 is formed of material selectedfrom the following group: ethylene-propylene-compound diene,acrylonitrile-butadiene, synthetic resinous fluorine, nylon,thermoplastic polyester elastomer, polyurethane, polyvinyl chloride andrubber.

In yet another variant, the stainless steel threads 30 are grouped intodistinct strands 40 that are interwoven to form at least one braidedlayer 45 of threads 30.

In a further variant, each strand 40 has between about two and aboutnine stainless steel threads 30.

In still a further variant, a gauge of the stainless steel threads 30ranges from about 0.002 inches to about 0.070 inches.

In another variant, the stainless steel threads 30 are located about theinterior tube 15 under tension and the tension ranges from about 0.5pounds to about 3 pounds.

In yet another variant, the moisture sensitive compound 32 is selectedfrom the group including copper sulfate, cobalt chloride, and cobaltiodide.

In a further variant, the flexible polymeric covering 35 is formed ofmaterial selected from the following group: ethylene-propylene-compounddiene, acrylonitrile-butadiene, synthetic resinous fluorine, nylon,thermoplastic polyester elastomer, polyvinyl chloride, polyurethane andrubber.

In yet another variant, the flexible polymeric covering 35 is about 0.8to 1.0 mm thick. The hose 10 is manufactured as follows.

A. The interior tube 15 is fabricated, preferably by extrusion.

B. At least one layer of stainless steel threads 30 is braided about theouter surface 25 of the interior tube 15.

C. The transparent, flexible polymeric covering 35 is fabricated,preferably by extrusion.

D. The moisture sensitive compound 32 is dispersed between the stainlesssteel threads 30.

E. The flexible polymeric covering 35 is slipped over the braid 30. Thistraps pockets of air 60 between the covering 35 and the braid 30 therebyprotecting the braid 30 from abrasion and corrosion and improving theinsulative properties of the hose 10. The moisture sensitive compound 32alerts the user to any leaks in the hose 10 through a visual inspection.

1. A method of manufacturing a reinforced flexible hose with leakageindicator comprising the steps of: A. fabricating an interior tube forconducting a fluid having an outer surface; B. braiding stainless steelthreads about said outer surface to form a braided layer; C. fabricatinga transparent flexible polymeric covering with inner diameter largeenough to fit over said braided layer; D. inserting a moisture sensitivecompound among said stainless steel threads; E. slipping saidtransparent flexible polymeric covering over said braided layer so thatsaid flexible polymeric covering contacts said stainless steel threadsin said braided layer tangentially; wherein pockets of air are trappedbetween said flexible polymeric covering and said stainless steelthreads, said stainless steel threads are protected from abrasion andcorrosion and the insulative properties of said hose are improved,moisture penetrating from said interior tube to said stainless steelthreads changes said moisture sensitive compound to said second color,indicating failure of said hose.
 2. The method as described in claim 1in which said interior tube is fabricated by extrusion.
 3. The method asdescribed in claim 1 in which said flexible polymeric covering isfabricated by extrusion.
 4. The method as described in claim 1, whereinsaid interior tube is formed of synthetic polymer material.
 5. Themethod as described in claim 1, wherein said interior tube is formed ofmaterial selected from the group comprising: ethylene-propylene-compounddiene, acrylonitrile-butadiene, synthetic resinous fluorine, nylon,thermoplastic polyester elastomer, polyurethane, polyvinyl chloride andrubber.
 6. The method as described in claim 1, further comprising thesteps of: A. grouping said stainless steel threads into distinctstrands; and B. interweaving said strands to form said braided layer. 7.The method as described in claim 6 in which each of said strandsincludes between about two and nine stainless steel threads.
 8. Themethod as described in claim 1, wherein a gauge of said stainless steelthreads ranges from about 0.002 inches to about 0.070 inches.
 9. Themethod as described in claim 1, in which said braiding step furtherincludes the step of keeping said stainless steel threads under tensionranging from about 0.5 pounds to about 3 pounds.
 10. The method asdescribed in claim 1, wherein said moisture sensitive compound isselected from the group comprising: Copper sulfate, cobalt chloride, andcobalt iodide.
 11. The method as described in claim 1, wherein saidflexible polymeric covering is formed of material selected from thegroup comprising: ethylene-propylene-compound diene,acrylonitrile-butadiene, synthetic resinous fluorine, nylon,thermoplastic polyester elastomer, polyvinyl chloride, polyurethane andrubber.
 12. The method as described in claim 1, wherein said flexiblepolymeric covering is about 0.8 to 1.0 mm thick.